Despite the severe health consequences associated with cigarette smoking, it remains the leading cause of preventable death in the world. Relapse rates following cessation remain high, imparting the need for the development of more effective treatment strategies. Therefore, it is imperative to explore the factors leading to relapse. Contemporary theories of tobacco use have proposed a self-medication model in which abstinence-related deficits may potentially lead to impulsive behavior. However, impulsivity is a broadly defined construct making it difficult to determine which dimensions are most important in relapse. Specifically, a smoker may experience a decrement in inhibitory control and an increase in delay-related impulsivity while abstinent. By attempting to alleviate these deficits, the unintended consequence may be relapse. The degree to which these abstinence-induced deficits are experienced may be associated with pre-existing symptoms. Individuals with disorders characterized by inhibitory deficits, such as Attention- Deficit/Hyperactivity Disorder (ADHD), report higher prevalence rates of smoking and lower cessation rates. To broaden understanding of the association among these processes, the proposed research will examine the effects of smoking abstinence on multiple aspects of inhibitory control and impulsivity in a sample of adult smokers selected for high and low levels of ADHD symptoms. In a within-subjects design, smokers will complete one session 12 hours deprived and one session non-deprived. The specific aims of the proposed study are: 1) examine abstinence effects on response inhibition (e.g., Stop-signal paradigm), interference control (e.g., attentional modification of startle), and delay-related impulsivity (e.g., delay discounting), 2) examine the relationships among these measures, 3) examine whether symptoms associated with preexisting deficits (i.e., ADHD symptoms) moderate the effects in Aims 1 and 2. Incorporating multiple measures of impulsivity will elucidate their interrelationships and whether they reflect core processes related to smoking behavior. A review synthesizing existing literature on genetic associations between smoking and ADHD will be written to examine whether impulsivity signifies an endophenotype of nicotine dependence. Further knowledge of the relationship between smoking withdrawal and impulsive behavior will provide insight into factors leading to the maintenance and relapse of smoking behavior. Treatments for ADHD that target these areas (i.e., inhibitory control, impulsivity) may be effective for smoking cessation or relapse prevention. These treatments may be particularly useful for at-risk populations (e.g., individuals who endorse ADHD symptoms or other impulse control problems).